Fuel

ABSTRACT

The invention relates to a fuel having an additive for increasing the calorific value, wherein the additive hardens and the handling of the fuel is thereby improved.

The invention relates to a fuel and a method for producing this fuel.

Fossil fuels in solid form and fuels from biomass have been known for along time. These fuels are needed in many branches of industry forvarious applications but are mainly used for generating electricalenergy or heat in power plants or for heating purpose in private areas.

Due to the increasing shortage and the rising costs for fuels, attemptsare being made to increase the calorific value of the fuels by means ofadditives.

It is known from U.S. Pat. No. 4,443,227 to treat charcoal with afatty-acid-based additive and WO 96/14372 discloses a fuel made oforganic materials which also has a fatty-acid-based additive.

A disadvantage of the additives used is that they do not harden and thefuel is always greasy after addition of the additive and loses theadditive again. As a result, this can have the consequence during longstorage that the fuel completely loses the additive and all theadvantages of the additive are lost.

In addition, the fuel must be transported and stored in specialpackagings since conventional packagings soften and tear due to theadditive or absorb the additive, which would result in an undesirablereduction of the additive in the fuel and in an increased fire risk.

With regard to the undesirable absorption of water, the fatty-acid-basedadditive in the prior art behaves in a hydrophobic manner andconsequently minimises the incorporation of water, but cannot completelyprevent this as a result of its continuously diminishing content in thefuel.

A further disadvantage of the fuel in the prior art is that the additivecannot prevent abrasion during transport and storage since the additivedoes not harden and does not impart any additional stability to thefuel.

When handling this fuel, the user must always wear gloves and take otherprotective measures to avoid contamination of hands and clothing by thegreasy additive.

These disadvantages are unsatisfactory both for the manufacturer and forthe purchaser and in addition increase the costs of this fuel.

It is therefore an object of the invention to provide a fuel having anadditive which increases the calorific value of the fuel, whichcompletely prevents incorporation of water, which exhibits no abrasionand which can easily be handled.

This object is achieved with a fuel having the features of claim 1 and amethod for producing such a fuel according to claim 6.

The basic idea of the invention is to treat a fuel with an additivewhich enhances the calorific value and hardens.

The fuel according to the invention and a preferred composition of theadditive are described hereinafter. Coal can be selected as a fossilstarting material for the fuel, wherein all types of coal, e.g. blackcoal, brown coal or charcoal are available for this purpose.

Any type of biomass is also suitable as starting material as analternative to a fossil starting material. Non-conclusive examples forthis are wood, wood chippings, grain such as wheat, rice, maize, rye,barley, oats or millet, starch, for example, from beans, peas orpotatoes, straw, all types of seeds such as olive seeds, palm oil seeds,sunflower seeds, pumpkin seeds and all cellulose-containing substances.

The fuel is preferably pressed into shaped pieces, wherein these shapedpieces can have any possible shape. So-called briquettes or pellets haveproved to be particularly suitable shapes.

Before the pressing process, the starting material can be present in anyform, i.e. in powder form, as chips etc.

It is understood that mixtures of black coal, brown coal, charcoal andthe biomasses are also suitable.

In the process, the starting material or the mixture thereof is pressedinto the desired shape at high pressure.

The additive according to the invention which is added to the startingmaterial comprises palmitic acid, stearic acid, lauric acid, myristicacid and oleic acid and comprises the following fractions:

50 to 60% palmitic acid

40 to 50% stearic acid

maximum 3% myristic acid

maximum 1% lauric acid

and traces of oleic acid.

The percentages can comprise both weight percentages and volumepercentages.

In this composition, the additive is present in a solid non-greasy formwhilst it has the same calorific-value-enhancing property as in theprior art. For this reason, the incorporation of water can no longerform in the fuel treated with this additive and the surface of the fuelis protected against abrasion or crack formation which reduces thebreaking of the fuel during transport. Consequently, there are no lossesof starting material or additive.

It is furthermore advantageous that the fuel need not be stored andtransported in any particular packaging since the fuel does not lose theadditive by greasing and does not release any type of dust and the userof the fuel need not take any protective measures against contaminationof clothing and hands.

If, for example, barbeque charcoal is treated with the additiveaccording to the invention, this improves the lighting behaviour andalso the handling of the barbeque charcoal since there is no risk ofcontamination to the hands.

In addition, this encapsulation by the additive prevents any formationof fine dust with the result that handling of the fuel is possiblewithout endangering the health of the user. If an increase in thecalorific value should only be of interest, the above composition of theadditive can be variably adjusted.

A method for producing this particular fuel is explained hereinafter.

During the production of the fuel, the additive can be processed both inthe solid and in liquid form. In solid form, the additive is blended inflake form or powder form with the starting material which can bepresent in any form. After producing a uniform mixture, this is pressedinto a specified shape at high pressure. During this pressing theadditive is distributed homogeneously inside the shaped pieces and formsa protective layer on the surfaces thereof.

Alternatively, prior to application, the additive can be heated aboveits specific melting point and used in liquid form. The specific meltingpoint of the afore-mentioned composition is around 62 degrees Celsius.

In this case, the pressing process of the starting material can becarried out both before and after treatment with the additive. Thetreatment of the starting material can be carried out by passing throughor dipping into a bath containing the liquid additive or by spraying iton. It should be mentioned that the treatment of the starting materialwith liquid additive has the advantage that the incorporated water isexpelled due to the hot additive, with the result that thecombustibility is further improved. The preferred temperature of theadditive when carrying out the treatment is between 70 and 90° but canbe higher or lower.

An alternative to the aforesaid additive is paraffin. Paraffin is awax-like, combustible, odourless, non-toxic and hydrophobic substancewhich, under certain conditions explained hereinafter has the relevantproperties for the invention.

Paraffin designates a mixture of alkanes, i.e. saturated hydrocarbons,wherein paraffin generally has the chemical molecular formulaC_(n)H_(2n+2) where n can be between 18 and 50. Depending on the chainlength, the melting point varies between 30 and 80° C. and the hardnessof the paraffin varies, with the advantageous possibility of selecting adesired melting point and degree of hardness depending on theapplication. Consequently, the method described above can be carried outunchanged with paraffin.

Paraffin can be used alone or in combination with the additive explainedabove, it having been found that a mixture with the aforementionedadditive has very good properties with a maximum fraction of 50%paraffin.

Furthermore, in cases in which merely an increase in the calorificvalues is desired, vegetable and animal fats can be used alone or in anymixing ratio. Non-conclusive examples for this are rapeseed oil,rapeseed methyl ester, sunflower oil, linseed oil, olive oil, coconutoil or coconut fat, palm oil seeds, soya oil and all compositions ofpalmitic acid, stearic acid, oleic acid, myristic acid and linoleicacid.

1. A fuel comprising a starting material with a first additive,characterised in that the additive comprises 50 to 60% palmitic acid, 40to 50% stearic acid, maximum 1% lauric acid, maximum 3% myristic acidand traces of oleic acid.
 2. The fuel according to claim 1 furthercomprising a second additive comprised of paraffin.
 3. The fuelaccording to claim 2, the first and second additives each defining afraction, the maximum fraction of the second additive being as large asthe fraction of the first additive.
 4. The fuel according to claim 1,the starting material being in shaped pieces.
 5. The fuel according toclaim 1, the starting material being selected from the group of coal,biomass or a mixture thereof.
 6. A method for producing a fuelcomprising the following steps: a) producing a starting material, b)adding an additive comprised of 50 to 60% palmitic acid, 40 to 50%stearic acid, maximum 1% lauric acid, maximum 3% myristic acid andtraces of oleic acid, and c) pressing the fuel into a particular shape.7. The method according to claim 6, wherein the additive is heated to atleast its specific melting point.
 8. The method according to claim 6further comprising adding another additive comprised of paraffin.
 9. Themethod according to claim 6, wherein the fuel is pressed before addingthe additive.
 10. The method according to claim 6, wherein the fuel ispressed after adding the additive.
 11. A method for producing a fuelcomprising the following steps: a) producing a starting material, b)adding an additive comprised of parrafin, and c) pressing the fuel intoa particular shape.
 12. The method according to claim 11, wherein theadditive is heated to at least its specific melting point.
 13. Themethod according to claim 11, wherein the fuel is pressed before addingthe additive.
 14. The method according to claim 11, wherein the fuel ispressed after adding the additive.
 15. The fuel according to claim 2,the starting material being in shaped pieces.
 16. The fuel according toclaim 15, the starting material being selected from the group of coal,biomass or a mixture thereof.
 17. The fuel according to claim 2, thestarting material being selected from the group of coal, biomass or amixture thereof.
 18. The fuel according to claim 4, the startingmaterial being selected from the group of coal, biomass or a mixturethereof.